1. Field of the Invention
The present invention relates to a kneader for a tooth restoration material, which circularly moves a capsule for a tooth restoration material while keeping its longitudinal direction in a fixed direction, in order to mix and knead a powder component and a liquid component of the tooth restoration material in a mixing compartment of the capsule for the tooth restoration material.
2. Description of the Conventional Art
In a dental treatment, the tooth restoration material is used for application, such as a filling, a luting, a lining or the like to restore the tooth by mixing and kneading the powder component and the liquid component immediately before using thereof. Thus, the capsule for the tooth restoration material, in which the fixed amounts of the powder component and the liquid component are weighed beforehand and housed isolatedly in the mixing compartment, is widely used in order to easily mix and knead those without soiling hands.
In general, the capsule for the tooth restoration material is used by breaking a partition or the like immediately before using thereof, and mixing and kneading two components, i.e., the powder component and the liquid component for the tooth restoration material. At this time, if the two components are not fully mixed and kneaded, the tooth restoration material becomes fragile, and if these components are mixed and kneaded excessively, the tooth restoration material is inconvenient to use since it is hardened immediately. Thus, the kneader for the tooth restoration material is used for exactly mixing and kneading. However, since the conventional kneader for the tooth restoration material only reciprocates the capsule for the tooth restoration material in one direction such as a longitudinal direction, there is a problem that the two components are not mixed and kneaded evenly since they receive the force only in the direction of the reciprocating movement of the capsule.
For solving the above problem, a kneader for a capsule for the tooth restoration material as follows is used in order to evenly mix and knead the two components for the tooth restoration material while they receive the force in various directions without generating bubbles in the mixed and kneaded material (for example, refer to Japanese Patent No. 3468367). The kneader comprises a capsule retaining chamber rotating means, which circularly moves the capsule retaining chamber itself for retaining the capsule for the tooth restoration material with its longitudinal direction being kept in a fixed direction, a driving means for driving the capsule retaining chamber rotating means, and a vacuum generator connected with the capsule retaining chamber. In the kneader for the capsule for the tooth restoration material, in order to circularly move a rotating table, where the capsule retaining chamber is rotatably supported around a fixed axis, the fixed axis and the capsule retaining chamber are connected with a timing belt so as to rotate the capsule retaining chamber in a reverse direction to the rotating direction of a pulley at the same angle as the rotating angle of the pulley fixed at the rotating table. Thus, the capsule retaining chamber on the rotating table circularly moves in the state of being kept in the fixed direction. Then, the two components for the tooth restoration material in the capsule for the tooth restoration material can be evenly mixed and kneaded while they receives the force in various directions.
However, in this kneader for the capsule for the tooth restoration material, the timing belt is used for rotating the capsule retaining chamber, and this timing belt is different from a general timing belt which is rotated and moved at high speed between the pulleys by the rotation of the pulley being compulsorily rotated. That is, when the rotating table is rotated around the fixed axis, this timing belt is rotated and moved at low speed around the fixed axis only at the angle as much as the rotating table is rotated, that is, the capsule retaining chamber is rotated with respect to the fixed axis. Thus, there is a problem that the accuracy of the timing belt cannot be kept when the timing belt is abraded or loosened even a little by the deterioration with the passage of time.
That is, in the conventional kneader for the capsule for the tooth restoration material, since the timing belt must be exactly rotated and moved around the fixed axis only at the angle as much as the capsule retaining chamber is rotated with respect to the fixed axis, the engaging accuracy of teeth of the pulley and the timing belt must be remarkably high. Further, since the timing belt formed with a rubber or the like is in the exposed state, a problem of the timing belt being quickly deteriorted or deformed is generated when chemicals or the like adhere. Thus, this conventional kneader is not preferably used in the dental treatment fields.